The general objective of the next year of studies is to continue work on cytoplasmic control of growth and quiescence in normal and neoplastic cells. Studies to date have shown that both spontaneously proliferating (transformed) and mitogen-activated normal cells contain a cytoplasmic protein (ADR) which is capable of inducing DNA synthesis in isolated quiescent nuclei. During the next year of support, the exact nature of ADR and its mechanism of action will continue to be investigated. A number of physicochemical techniques, including gel filtration, ion-exchange chromatography, and electrophoresis will be used to partially purify and characterize ADR from both normal and neoplastic cells. In addition, this laboratory will investigate whether ADR binds to the nuclear membrane or whether ADR is a DNA-binding protein by testing its ability to bind to DNA-cellulose. Another set of studies will involve the activation of intact cells by the intracellular delivery of ADR in red blood cell ghosts. During the last year, this technique was worked out using fluorochrome-labeled proteins. We will now attempt to activate resting cells by delivering both crude and partially-purified ADR preparations. If the red cell ghost method proves unsuccessful, alternate techniques such as osmotic lysis of pinocytic vesicles will be employed. Finally, we plan to continue studies on the cellular regulation of ADR activity. Recently, we found that normal resting lymphocytes contain a heat-stable protein which is capable of inhibiting ADR activity from both normal and neoplastic cells. These studies will be continued during the next year to further elucidate the nature and role of this molecule in the control of cellular proliferation. (I)